Problem with Takagi & Radiant Heat &Domestic Hot Water

Last year I remodeled my home and installed plex tubing throughout my 2 unit building. Upon the advise from a company back in Vemont, I installed a Takagi Jr. to run the radiant heat and domestic hot water supply.

The downstairs unit works like a charm with no problems (although I did have to remove all flow restrictors from faucets and shower/bath tub).

The big problem is with the upstairs unit. Back in February, the domestic hot water seems only to work when the radiant system is turned on and burning. I called Takagi twice and they sent 2 repairmen but they looked overwhelmed by the system and said the system works fine and they could not find anything wrong with the water heater.

I shut off water to the tankless and turned on the hot water to a facet upstairs and found there was no cross water line. The company who sold me the pre-assembled board is going to send me a new one provided I do not ask them for any more technical advise (which by the way, I spend nearly $1500 on all new faucets and replacing the shower unit).

I am now in a situation where everyone is pointing fingers at each other. Takagi says something is wrong with the plumbing, Vermont Company is saying its the Takagi, and the plumber saying there is no cross water lines.

Frustrated, I am ready to let the Takagi Jr. take care of the radiant heating supply and I will install back a traditional hot water tank.

I was so frustrated that I even offered to buy an airline ticket for an employee of the Vermont company that sold me the system to come out West. Their response was take a new set up but don't call us anymore.

My tenants have been very patient but I want to give it one last try to fix the system. It works so well down stairs. I am going to swap machines to see if this helps and prove once and for all if it is indeed the heater.

Could I have the wrong size Takagi? The upstairs has 2 bathrooms, kitchen, and washer.

How many BTU does the thing draw? What's its rated gallons/minute? I assume you have a heat exchanger for the radiant heat, as you wouldn't want to run potable water through all those lines.

What is the heat load on the house? In other words, how much heat do you need in your boiler (heater)? Does the system operate with priority zones? If the priority scheme is not set up properly, (i.e., when you call for hot water for washing, showering, etc.), if it is still providing heat to the heat exchangers for space heating, the potable water will never get hot enough. It needs to bypass the heat exchangers. If the zone valve or pump is still running, you won't get any hot water for the shower. Both units need to restrict flow to the heat exchanger(s). A diagram of what you have might be useful.

It could be as simple as a stuck or improperly positioned check valve, zone valve, or pump.

I'm not a fan of using a potable water heater (tankless or conventional) for space heating.

I too have a problem with my water TAKAGI water heater. We bought a T_K2. It lasted about four years then the dreaded number 12 error code comes up. Takagi tech support was very unknowledgeable. We sand and dismantle, and clean and spray, still nothing. They then blame it on the gas pressure. Gas company came out four times, to make us happy, they changed out the regulator, the meter, and measured the pressure. Nothing is wrong except the Takagi system. Now the company blamed it on installation. It was installed and inspected, and working for four years. hmmmm. They will not negotiate or work with us. Offered us an upgrade at an outrageous price, said I could pick one up cheaper on the internet. Whoa, what do you mean cheaper, if you don't buy it from us then we won't honor the warranty even though it's a brand new unit from an internet store..not ****..said the TAKAGI rep. Not only that but they called back and harrass me about the name of the internet company that sell their product cheaper then them. I have no hot water, my daughter is crying, and they worry about someone undercut them? We have gone back to the tank system, phew...hot water...a word of advise, tankless system doesn't really save energy, water pressure weak if you use hot water at more than one faucet, and when it's time for repair, don't call a plumber because all they know how to do is install. If you really want to go with tankless, stay away from TAKAGI...try Rheem, at least GE stand behind their products.

I too have a problem with my water TAKAGI water heater. We bought a T_K2. It lasted about four years then the dreaded number 12 error code comes up. Takagi tech support was very unknowledgeable. We sand and dismantle, and clean and spray, still nothing. They then blame it on the gas pressure. Gas company came out four times, to make us happy, they changed out the regulator, the meter, and measured the pressure. Nothing is wrong except the Takagi system. Now the company blamed it on installation. It was installed and inspected, and working for four years. hmmmm. They will not negotiate or work with us. Offered us an upgrade at an outrageous price, said I could pick one up cheaper on the internet. Whoa, what do you mean cheaper, if you don't buy it from us then we won't honor the warranty even though it's a brand new unit from an internet store..not ****..said the TAKAGI rep. Not only that but they called back and harrass me about the name of the internet company that sell their product cheaper then them. I have no hot water, my daughter is crying, and they worry about someone undercut them? We have gone back to the tank system, phew...hot water...a word of advise, tankless system doesn't really save energy, water pressure weak if you use hot water at more than one faucet, and when it's time for repair, don't call a plumber because all they know how to do is install. If you really want to go with tankless, stay away from TAKAGI...try Rheem, at least GE stand behind their products.

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These sorts of problems and complaints will begin to multiply as more and more of this junk is foisted on a market hungry to do the green thing. It's amazing how we never seem to learn from the mistakes of the past, a la ELM Aquastar and Paloma Pak. Very similar units with all the same technical problems as the current incarnations.

I too have a problem with my water TAKAGI water heater. We bought a T_K2. It lasted about four years then the dreaded number 12 error code comes up. Takagi tech support was very unknowledgeable. We sand and dismantle, and clean and spray, still nothing. They then blame it on the gas pressure. Gas company came out four times, to make us happy, they changed out the regulator, the meter, and measured the pressure. Nothing is wrong except the Takagi system. Now the company blamed it on installation. It was installed and inspected, and working for four years. hmmmm. They will not negotiate or work with us. Offered us an upgrade at an outrageous price, said I could pick one up cheaper on the internet. Whoa, what do you mean cheaper, if you don't buy it from us then we won't honor the warranty even though it's a brand new unit from an internet store..not ****..said the TAKAGI rep. Not only that but they called back and harrass me about the name of the internet company that sell their product cheaper then them. I have no hot water, my daughter is crying, and they worry about someone undercut them? We have gone back to the tank system, phew...hot water...a word of advise, tankless system doesn't really save energy, water pressure weak if you use hot water at more than one faucet, and when it's time for repair, don't call a plumber because all they know how to do is install. If you really want to go with tankless, stay away from TAKAGI...try Rheem, at least GE stand behind their products.

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So your Takagi worked great for you for four straight years without any problems. I am assuming you didn't maiuntain it throughout those four years. You probably also have the unit installed in a laundry room. This type of installation would cause the burners to slowly plugg up and lead to the error code that you described. This is not the fault of the unit. A simple solution would be to remove the burner and use compressed air to blow the particles that have built up inside of the burner over the years. You should also check your heat exchanger finns at this point to see if that is blocked as well. If it is, blow that out as well and that should take care of the problem. If it does not, then your overheat cut-off fuse may simply be weak and needs to be replaced. This is also a problem that could be caused by blockage in the burner or heat exchanger coils/fins.

Good Luck with your unit, but it is not the fault of the water heater. Takagi tankless have an excellent repulation and only poor installations for the most part give tankless water heaters in general a bad reputation.

I too have a problem with my water TAKAGI water heater. We bought a T_K2. It lasted about four years then the dreaded number 12 error code comes up. Takagi tech support was very unknowledgeable. We sand and dismantle, and clean and spray, still nothing. They then blame it on the gas pressure. Gas company came out four times, to make us happy, they changed out the regulator, the meter, and measured the pressure. Nothing is wrong except the Takagi system. Now the company blamed it on installation. It was installed and inspected, and working for four years. hmmmm. They will not negotiate or work with us. Offered us an upgrade at an outrageous price, said I could pick one up cheaper on the internet. Whoa, what do you mean cheaper, if you don't buy it from us then we won't honor the warranty even though it's a brand new unit from an internet store..not ****..said the TAKAGI rep. Not only that but they called back and harrass me about the name of the internet company that sell their product cheaper then them. I have no hot water, my daughter is crying, and they worry about someone undercut them? We have gone back to the tank system, phew...hot water...a word of advise, tankless system doesn't really save energy, water pressure weak if you use hot water at more than one faucet, and when it's time for repair, don't call a plumber because all they know how to do is install. If you really want to go with tankless, stay away from TAKAGI...try Rheem, at least GE stand behind their products.

Last year I remodeled my home and installed plex tubing throughout my 2 unit building. Upon the advise from a company back in Vemont, I installed a Takagi Jr. to run the radiant heat and domestic hot water supply.

The downstairs unit works like a charm with no problems (although I did have to remove all flow restrictors from faucets and shower/bath tub).

The big problem is with the upstairs unit. Back in February, the domestic hot water seems only to work when the radiant system is turned on and burning. I called Takagi twice and they sent 2 repairmen but they looked overwhelmed by the system and said the system works fine and they could not find anything wrong with the water heater.

I shut off water to the tankless and turned on the hot water to a facet upstairs and found there was no cross water line. The company who sold me the pre-assembled board is going to send me a new one provided I do not ask them for any more technical advise (which by the way, I spend nearly $1500 on all new faucets and replacing the shower unit).

I am now in a situation where everyone is pointing fingers at each other. Takagi says something is wrong with the plumbing, Vermont Company is saying its the Takagi, and the plumber saying there is no cross water lines.

Frustrated, I am ready to let the Takagi Jr. take care of the radiant heating supply and I will install back a traditional hot water tank.

I was so frustrated that I even offered to buy an airline ticket for an employee of the Vermont company that sold me the system to come out West. Their response was take a new set up but don't call us anymore.

My tenants have been very patient but I want to give it one last try to fix the system. It works so well down stairs. I am going to swap machines to see if this helps and prove once and for all if it is indeed the heater.

Could I have the wrong size Takagi? The upstairs has 2 bathrooms, kitchen, and washer.

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Could it be that the upstairs is connected in series with the recirculation pump that runs the heating application? If this is the case, your upstairs fixture simply will not operate unless the pump is running. Take a look at the set-up and see if there is a pump located before the line that tees off to the fixture that you are speaking about.

If you can post a diagram of the system, I would be able to identify your problem.

These sorts of problems and complaints will begin to multiply as more and more of this junk is foisted on a market hungry to do the green thing. It's amazing how we never seem to learn from the mistakes of the past, a la ELM Aquastar and Paloma Pak. Very similar units with all the same technical problems as the current incarnations.

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He used his water heater for four years, not problems. Didn't maintain it, and now it doesn't work any more. Okay, lets blame it on the water heater why don't we.

Fact of the matter is everything needs maintenance. Unfortunately, the people that were sent to this guy didn't know about the units and the installers did not take the time to learn enough about the product prior to installing it. Tankless have been in other parts of the world for over 60 years and no one is complaining about them. If they were horrible, why is the technology still alive. Tell anyone from Europe that you have a storage tank type water heater and they will laugh at you.

As for GE and Rheem, good luck with them, since they don't even manufacture their own products. If you really truly want a good tankless water heater, do your research and make sure that you purchase a Japanese model as they have the most stringent design criteria.

These sorts of problems and complaints will begin to multiply as more and more of this junk is foisted on a market hungry to do the green thing. It's amazing how we never seem to learn from the mistakes of the past, a la ELM Aquastar and Paloma Pak. Very similar units with all the same technical problems as the current incarnations.

Click to expand...

this week, I have had 3 people call me about their tankelss water heaters..

all 3 were Bosches, all three had broken down... with no one in town wanting to work on them

It kind of Reminded me of the story of the 3 little pigs....and I was the Big Bad Wolf......

Piggey #1 the first lady was rather huffey with me , telling me how she was saveing the palnet, and we all got to do our part.. and she whoud find someone else more competent to repair her unit in the yellow pages.....

I was not going to explain anything to , and her mind was made up.

I would love to hear how that search went and the cost of the to her 6 year old Bosch tankless.

Piggey #2 This fellow decided to install his Bosch into his regular furnace flu pipegoing up the center of his home... ........oh my goodness, thats a no..no........

I told him that he might burn his home down thatway, because his metal chimmney was not designed or rated for the intence heatthat the tankless would put out,I dont think he wanted to hear what I had to sayI was being too blunt explaining to him thatthat his house might burn down.....

Piggey #3 I did not even waste my time trying to help her, I figured what was the use....its all gonna fall on deaf ears..

99* Of Takagi calls i go on i find a reason they are not functioning. Its always the same story, Bad venting, gas issues, poor placement or just no maintenance. I thought i was a tankless pro until i went to Takagi's plant in California for their training class. Needless to say i discovered i was far from it. People blame the units but in most cases it is the installer or the owner.

99* Of Takagi calls i go on i find a reason they are not functioning. Its always the same story, Bad venting, gas issues, poor placement or just no maintenance. I thought i was a tankless pro until i went to Takagi's plant in California for their training class. Needless to say i discovered i was far from it. People blame the units but in most cases it is the installer or the owner.

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how do you handle a situation where the home might burn down becasue of the way the home owner installed their tankless waterheater???

do you just write a warning on the bill you hand them to cover any future liability????

Piggey #2 This fellow decided to install his Bosch into his regular furnace flu pipegoing up the center of his home... ........oh my goodness, thats a no..no........

I told him that he might burn his home down thatway, because his metal chimmney was not designed or rated for the intence heatthat the tankless would put out,I dont think he wanted to hear what I had to sayI was being too blunt explaining to him thatthat his house might burn down.....

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S'plain me better about this intense heat the tankless is puttin' out?

I thought the problem for most tankless vent was the coolness of the exhaust creating a potential for flue condensation & corrosion, but those bottom-of-the line atmospheric-drafted Bosch units are low enough efficiency that with the designed-in dilution air makes 'em ventable with the cheap B-vent (provided the draft is sufficient for both appliances whether one or both were firing.)

Some may require double-wall B-vent, but only the higher end forced draft versions require Z-vent. But again, it's the LACK of intense heat and the relatively high dew point of the undiluted exhaust of the forced draft versions that's the problem, not the high heat intensity that's the problem.

Vented into improper stack types I'd be more concerned about carbon monoxide hazard from corrosion pinholes than fire.

Some of the tankless systems use 200K BTU or more, which is a pretty fair amount of heat. Even at their best efficiency, the flue temp can be pretty high. And, the volume of air is substantial, too. Don't put one in without either closed combustion or adequate makeup air and, follow the flue requirements of the manufacturer carefully.

Some of the tankless systems use 200K BTU or more, which is a pretty fair amount of heat. Even at their best efficiency, the flue temp can be pretty high. And, the volume of air is substantial, too. Don't put one in without either closed combustion or adequate makeup air and, follow the flue requirements of the manufacturer carefully.

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I'm not sayin' that there couldn't be any number of problems with the installation, only that most fuggups would lead to a CO poisoning hazard before a fire hazard.

Most of the cheapo atmospheric vented BOSCH units are under 150kbtu in, and don't have flue temps any hotter than the output of similar-sized furnace burners, and run about 80-82% combustion efficiency. But I could easily believe the height/diameter of the stack wasn't up to snuff for both appliances. But there are plenty of B-vented multi-appliance stacks in the world that aren't hazards, even if the appliance vendor (rightly) warns against doing it that way. (IIRC in MA it's allowed, but the draft has to be empirically proven. Cood be rong, offen am...)

A typical 25% excess air atmospheric vented burner running in the 80% range will have a net-stack temp of ~400F (which would be ~465F if the combustion air is drawn from a typical basement) before dilution air, but the dilution air brings down to ~300F entering the vent, with the dew point of the exhaust lowered to 100F or less. This is where I'd expect the cheap Bosch units to live. If it's efficiency is in the low 70s the net stack temp might be 600F, but I don't think any tankless units sold run combustion efficiencies much lower than 77-78%, which would be ~500F net, at which point it could withstand huge dilution cooling with no chance of stack condensation, even in a masonry chimney, yet scant fire hazard unless the vent was installed with non code-compliant clearances to combustibles.